Screed chair



April 4, 1944.

B. HILLBERG.

SCREED CHAIR Filed Feb. 12, 1942 Patented Apr. 4, 1944 UNITED STATES 2,345,976 scream) crmna Bror Hillberg; Chicago, Ill., assignor t'o- Superior" Concrete Accessories, Chicago,- 111;, a partnership Application-February 12, 1942,1SeriaLNo. 430,555

1 Claim:

The present invention relates generally to chairs for use in connection with the formation" of concrete slabs. More. particularly the invention relates to that type of chair whichis adapted in conjunction with a series of like chairs to support a screed; comprises a base and a verticallyadjustable,screed-supporting bracket on the base, and is designed to become embedded in the concrete. duringpouring' of the latterfor slab forming purposes.

In using a screedchair of this type the chair is first positioned on the formor'supporting sur= face over which the slabis to be formed. Thereafter'the bracket is adjusted so thatit will hold: the screed in such position that theupper surface thereof is flush or coplaner with the desired top level of theslab-to be formed. After proper adjustment of the bracketthe screed is mountedon the bracket and; concrete is poured over the form or supporting surface until it builds up to a point wherein the: top surface thereof is level with the upper portion of the screed. While the concreteis still in a wet orrplastici state astraight' edge is moved: across the screedlso as properly to level the concrete. Afterithe concrete levelling operation the screed'andibra'cket are removed; Prior to setting or hardeningiof the concrete the cavities resulting from removal of" the screedl andbracket are filled soas to: complete the slab: Inpractice itihasbeen found that-zin many instances the slab',. after being poured and while'thecomcrete ism a; plastic or wet state; settles or shifts downwards sothatthe upper" surface thereof is below the desired level. This is sometimes attributable to a faulty form'- and" necessitates an upward adjustment of the bracket so as to bring the upper portion of the screed to the proper or desiredtop level-for the slab. It further necessitates an additional pouring ofconcrete inorder to. build-the slab up to the desired or prescribedlevel. Previously designedscreed' chairs of the type under considerationare subject to the obj'ection that when during use of the chairsit is' necessary, because of'sagg-ingof the wetcon'crete', to adjust vertically the bracket'sfor screed raising. purposes the adjustment can only be made byremovingthe-screed from the chair brackets;

The primary object: of the invention is topr'ovide a screed chair which is an improvement upon, and eliminatesthe objectionable features of previously designedchairs of'tlie same general design and for the same purpose and ischarac terized by the factthat'thescreed-supporting or holding bracket may be readily? adjusted. as to height afterpouring cfthe slab: andtwlthout the necessity of removing; thescreed from the bracket. Ingeneral theimproved' screed chair comprises a lag screw or like threaded element, the lower end of which'fitswithin ankinternally-threaded socket on the base and the upper endof which extends loosely' through a hole in the bracket, and has above the bracket a polygonal head whereby the screw or element may be turned for adjustment purposes by aiwrench' or similar turning'tocl;

Another. object of the invention is to provide a screed chair of the last mentioned character imwhichzthe bracket-is held against vertical displacement Withi respect to the lagscrew by way of a collar'beneath the head of the screw and is shaped so. as to. receive and support either a screed ofthepipe type or abar type. screed.

A further object-of the invention is toprovide a screed chair which is generally of new and improved construction, efiectively and .efficiently fulfills its intended,purpose-,.and.is so designed or constructed that it: maybe produced at a comparatively low cost Other: objects of the invention and the various advantages" and. characteristics of the present screed chair will be apparent from aconsideration of'thevfollowing detailed description.

The: invention consists. in: the several novel features which are hereinafter set forth and are moreparticularly. definedby thezclaim atithe cona,- partof this specification or disclosure and in which like letters and-numerals of reference denote corresponding. parts throughout the several views:

Figure 1 isaperspective of a screed chair embodying the invention Figure 2 is av section showing the improved chair in itsoperative position with respect to a screed and'embedded in a freshly poured slab of concrete; and

Figure 3 is av section showing the slab after removal of the screed and the chair bracket but .prior to filling of" the cavities resulting from removal of thescreed and bracket;

The screed chair which is shown-in the drawing constitutes the preferred form or embodiment of the-invention; Itis designed'tosupport either a pipetypescreed S or abar type-screed S in: connection with formation of" a concrete slab S on a horizontal surface S Asits parts the chair comprisesalbase 4-, a lag screw 5 anda screed supporting brackete- The base 41is1adapted' to rest on the-supporting eurface-v S3 during pouring of the concrete-for the slab S and is adapted to remain in the slab and form a reenforcement for the latter. It may :be nailed or otherwise anchored to the supporting surface S and consists of a vertical elongated internally threaded socket and a pair of depending U-shaped legs 8 for supporting the socket in an elevated position with respect to the supporting surface. The socket I is preferably in the form of a wire helix in order to reduce to a minimum the production cost of the chair. The legs 8 are formed of wire and are disposed in opposed relation, as best shown in Figure 1 of the drawing. The side pieces of the legs are arranged in upwardly convergent fashion and have vertically extending upper extremities which are welded or otherwise fixedly secured to the internally threaded socket I. The central portions of the cross pieces of the U-shaped legs 8 are bent upwards so that the lower corners of the legs form feet for engaging the supporting surface S and maintaining the base 4 in a stable position when in place on the supporting surface. The lag screw 5 extends vertically through the internally threaded socket I, as shown in the drawing, and comprises an elongated shank 9 and a head Ill. The lower end of the shank has an external screw thread of the same size and pitch as the female or internal screw thread of the socket I. The head I is located at, and formed integrally with, the upper end of the shank 9 and is polygonal in contour so that it may be gripped by a wrench or similar turning tool in connection with turning of the lag screw 5. When the lag screw is turned in one direction it moves downwards with respect to the base due to the action of the screw conhection between the shank of the lag screw and the socket of the base. When the screw is reversely rotated or turned it moves or feeds upwards relatively to the base.

The bracket 6 of the chair is in the form of a one-piece stamping consisting of a horizontally extending central or intermediate part II, a U- shaped part I2 at one end of the intermediate part and a substantially semi-circular part I3 at the other end of the intermediate part. The intermediate part I I of the bracket has a central hole I4 which is of slightly greater diameter than the'shank 9 of the lag screw 5. The upper end of the lag screw shank extends loosely through this hole with the result that the screw is permitted to rotate freely relatively to the bracket. The upper face of the intermediate part I I of the bracket underlies the polygonal head I0 of the lag screw. The bracket is held against vertical displacement relatively to the lag screw by way of a collar I5 which underlies the intermediate part II of the bracket and is welded or otherwise fixedly secured to the upper end of the lag screw shank at a point directly beneath the head I0. When the lag screw is turned in connection with vertical adjustment thereof the bracket moves up or down with the screw, depending upon the direction in which the screw is rotated,

while at the same time it does not rotate with the screw. The U-shaped part I2 of the bracket is adapted to receive and hold the bar type Screed S and the substantially semi-circular end part E3 of the bracket is adapted and designed to hold,

cular end part I3. The bracket, because it embodies a U-shaped end part and a substantially semi-circular end part, is capable of supporting either type of screed. The depth of the U-shaped part I2 of the bracket is such that when a standard bar type screed is supported by it the upper face of such screed is disposed slightly above the upper face of the head ID of the lag screw 5. The substantially semi-circular end part I3 of the bracket is adapted to receive a pipe type screed of standard size and is of such depth that when the pipe type screed is supported :by it the upper portion of the screed is disposed slightly above the upper face of the screw head I0. By reason of'the fact that such head is at the upper end of the screw and is disposed above the intermediate part of the bracket the screw may be turned from above in connection with vertical adjustment of the screed supporting bracket 6 and it is unnecessary to remove the screed.

In using the chair in connection with formation of the concrete slab S the chair is placed on the supporting surface S in alignment with a group of similar chairs. Thereafter the base 4 is nailed or otherwise secured to the supporting surface. relation with the supporting surface by way of staples around the intermediate pieces of the 'U-' shaped legs 8. After anchoring of the base the lag screw 5 is adjusted so as to bring the bracket 6 to the proper height. After turning or adjustment of the screw a screed is placed on the bracket. If the pipe type screed S is used it is mounted in the substantially semi-circular end part I3 of the bracket, as shown in Figure 2. It is contemplated that the adjustment of the bracket will be such that the upper portion of the pipe type screed will be flush or coplaner with the desired top level of the slab. After mounting of the screed on the bracket concrete is poured onto the supporting surface S until it builds up to the upper portion of the screed, as shown in Figure 2. After pouring of the concrete a straight edge is moved across the screed so as properly to surface or level the slab. In the'event that the screed from the bracket. In connection .with anauxiliary or secondary raising of the bracket it is only necessary to apply a wrench to the head Ill of the lag screw and then turn the Wrench in order to efiect the desired adjustment. After the second or auxiliary adjustment of the bracket additional concrete is poured until it builds up to the proper or desired level. While the concrete is in a wet or plastic state the screed is first removed. Thereafter the bracket and screw are removed by turning the screw out of connected relation with the socket of the base 4. Upon removal of the screed, bracket and lag screw the resulting cavities (see Figure 3) are filled with concrete. The bracket and lag screw of the chair, as well as the screed, are reusable. Upon completion of the slab due to hardening or setting of the concrete, the base 4 is permanently embedded in the slab and serves as a metallic reenforcement for the-latter.

The herein described screed chair may bemanufactured at a reasonably low cost and effectively and emciently fulfills its intended purpose. It

If desired the base may be held in fixed.

is characterized by the fact that it may be readily adjusted after pouring of the concrete therearound without necessitating removal of the screed. It is further characterized by the fact that it is capable of supporting or holding either a pipe type or a bar type screed.

The invention is not to be understood as restricted to the details set forth since these may be modified within the scope of the appended claim without departing from the spirit and scope of the invention.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

A chair designed to support a screed over a supporting surface in connection with formation of a concrete slab and comprising a base adapted to rest on the supporting surface and consisting of a vertical internally threaded socket and a pair of opposed depending U-shaped legs having the side pieces thereof upwardly convergent and secured at their upper extremities to the socket, a vertical lag screw embodying an externally threaded shank within the socket and. a fixed polygonal head at the upper end of the shank and adapted when the head is gripped by a wrench or other tool and then turned to move relatively to the :base, a bracket having a part 

